This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Hamamatsu Photonics has developed a prototype dual channel time domain tissue oximeter. Hamamatsu is currently searching for applications for which this device may be used. Tests of instrument signal-to-noise, stability, user and patient interfaces, and overall system performance will be assessed.